# Copyright 2013, Red Hat, Inc.
#
#    Licensed under the Apache License, Version 2.0 (the "License"); you may
#    not use this file except in compliance with the License. You may obtain
#    a copy of the License at
#
#         http://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
#    License for the specific language governing permissions and limitations
#    under the License.

"""
Client side of the scheduler manager RPC API.
"""

from oslo.config import cfg
from oslo import messaging

from nova.objects import base as objects_base
from nova.openstack.common import jsonutils
from nova import rpc

rpcapi_opts = [
    cfg.StrOpt('scheduler_topic',
               default='scheduler',
               help='The topic scheduler nodes listen on'),
]

CONF = cfg.CONF
CONF.register_opts(rpcapi_opts)

rpcapi_cap_opt = cfg.StrOpt('scheduler',
        help='Set a version cap for messages sent to scheduler services')
CONF.register_opt(rpcapi_cap_opt, 'upgrade_levels')


class SchedulerAPI(object):
    '''Client side of the scheduler rpc API.

    API version history:

        1.0 - Initial version.
        1.1 - Changes to prep_resize():
                - remove instance_uuid, add instance
                - remove instance_type_id, add instance_type
                - remove topic, it was unused
        1.2 - Remove topic from run_instance, it was unused
        1.3 - Remove instance_id, add instance to live_migration
        1.4 - Remove update_db from prep_resize
        1.5 - Add reservations argument to prep_resize()
        1.6 - Remove reservations argument to run_instance()
        1.7 - Add create_volume() method, remove topic from live_migration()

        2.0 - Remove 1.x backwards compat
        2.1 - Add image_id to create_volume()
        2.2 - Remove reservations argument to create_volume()
        2.3 - Remove create_volume()
        2.4 - Change update_service_capabilities()
                - accepts a list of capabilities
        2.5 - Add get_backdoor_port()
        2.6 - Add select_hosts()

        ... Grizzly supports message version 2.6.  So, any changes to existing
        methods in 2.x after that point should be done such that they can
        handle the version_cap being set to 2.6.

        2.7 - Add select_destinations()
        2.8 - Deprecate prep_resize() -- JUST KIDDING.  It is still used
              by the compute manager for retries.
        2.9 - Added the legacy_bdm_in_spec parameter to run_instance()

        ... Havana supports message version 2.9.  So, any changes to existing
        methods in 2.x after that point should be done such that they can
        handle the version_cap being set to 2.9.

        ... - Deprecated live_migration() call, moved to conductor
        ... - Deprecated select_hosts()

        3.0 - Removed backwards compat

        ... Icehouse supports message version 3.0.  So, any changes to
        existing methods in 3.x after that point should be done such that they
        can handle the version_cap being set to 3.0.
    '''

    VERSION_ALIASES = {
        'grizzly': '2.6',
        'havana': '2.9',
        'icehouse': '3.0',
    }

    def __init__(self):
        super(SchedulerAPI, self).__init__()
        target = messaging.Target(topic=CONF.scheduler_topic, version='3.0')
        version_cap = self.VERSION_ALIASES.get(CONF.upgrade_levels.scheduler,
                                               CONF.upgrade_levels.scheduler)
        serializer = objects_base.NovaObjectSerializer()
        self.client = rpc.get_client(target, version_cap=version_cap,
                                     serializer=serializer)

    def select_destinations(self, ctxt, request_spec, filter_properties):
        cctxt = self.client.prepare()
        return cctxt.call(ctxt, 'select_destinations',
            request_spec=request_spec, filter_properties=filter_properties)

    def run_instance(self, ctxt, request_spec, admin_password,
            injected_files, requested_networks, is_first_time,
            filter_properties, legacy_bdm_in_spec=True):
        msg_kwargs = {'request_spec': request_spec,
                      'admin_password': admin_password,
                      'injected_files': injected_files,
                      'requested_networks': requested_networks,
                      'is_first_time': is_first_time,
                      'filter_properties': filter_properties,
                      'legacy_bdm_in_spec': legacy_bdm_in_spec}
        cctxt = self.client.prepare()
        cctxt.cast(ctxt, 'run_instance', **msg_kwargs)

    def prep_resize(self, ctxt, instance, instance_type, image,
            request_spec, filter_properties, reservations):
        instance_p = jsonutils.to_primitive(instance)
        instance_type_p = jsonutils.to_primitive(instance_type)
        reservations_p = jsonutils.to_primitive(reservations)
        image_p = jsonutils.to_primitive(image)
        cctxt = self.client.prepare()
        cctxt.cast(ctxt, 'prep_resize',
                   instance=instance_p, instance_type=instance_type_p,
                   image=image_p, request_spec=request_spec,
                   filter_properties=filter_properties,
                   reservations=reservations_p)
